The present invention relates to a developing device for developing latent images formed on an image support which is used in, e.g., the electronic photographing or recording apparatus.
In a developing process of this type, developer is carried from its container to the image support by means of the developer carrier. Part of the carried developer is held on the image support to contribute to the developing of an image, while the rest is collected as residual developer, which does not contribute to the developing of the image. This residual developer is again returned to the container.
With the conventional developing device, a cylinder-like drum, for example is arranged as the developer carrier between the developing position adjacent to the image support and the container in which the developer is contained. When the drum is rotated, the drum surface picks up the developer from the container, carries it toward the image support, and then returns the amount left on the drum surface which does not assist in the developing of the image back to the container again. The conventional developing device therefore needs a driver means for driving the cylinder-like drum. In addition, a magnetic roll is arranged inside the drum to enable the drum surface to hold the developer. And this magnetic roll must also be driven. The conventional developing device which needs the driver means as described above can become complicated, large-sized and high in cost accordingly.